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tv   [untitled]    April 12, 2012 4:00pm-4:30pm EDT

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and ours impermeable formations and so this is one of those sources, tight gas, sand and carbonate and other rocks, and methane in the green there is sometimes fracked in order to produce the gas. the other sources are conventional sources, and you can see that there -- our production domestically in decline. that's why the long-time use of hydro fracking for tight gas and then the more recent use for shale gas is so important. you can see, if you subtracted those wedges, that we would have a much less -- much less domestic production, and we would have to be importing that gas to replace that production.
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the usgs, then, our role is to try to -- one of our roles is to try to assess how much undiscovered gas might be out there, yet to be discovered, using current knowledge and technology. and to go back to this slide, this is all on the right-hand side, a projection. in order to make that projection, you need to have an assessment of how much gas is yet to be discovered. so we use standardized methodologies that are based on gee logic model that we prepare, and then we apply some statistical or probabilistic approaches to try to estimate how much gas might be out there yet to be discovered. and that's an uncertain business, which is why we use these probabilistic approaches. and we use -- because of the transparency of our methodologies and the consistent see of our methodologies, our assessments are used by a wide variety of people, including land managers of our federal
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lands, our congress, and state congressional delegations, for example. the public, nongovernmental organizations. and as well as industry. so let me step back just a little bit so we understand what an unconventional resource a little bit better. this diagram is sort of a cartoon, cross section to the earth. conventional oil and gas resources occur in pools or reservoirs that are constrained on the top and on the sides by impermeable zones. and they often have an oil/water contact or gas/water contact. and unconventional resources, we technically refer to them as con tenuous resources because the oil resource or gas resources is distributed con tenuously through the formation at depth. and the rock is so impermeable or tight and that's why we need
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to use techniques such as hydro fracking and horizontal drilling to extract the resource. one example of the resource assessment is our recently completed marcellus shale gas assessment in the northeastern united states. being from this area, you probably heard of it, or maybe not. but at the bottom, i list here what our mean estimate, which was 84 trillion cubic feet of gas. but it also shows that -- our estimate is it could be as low as 43 trillion cubic feet or as high as 144 trillion cubic feet. so, again, this illustrates the uncertainty that's associated with some of these assessments -- methodologies, and these are estimates, after all. what do we do with these assessments after we're done? this -- these maps that i show here, the lower right one, is a compilation of the assessments that we have done of a number of
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unconventional resources. gas resources in the united states. and you can see that there's -- maybe you can't read the number, but there's quite a bit of gas, over 600 trillion cubic feet. and in the upper left is our map of the conventional resources. and with the exception of the gulf coast, and alaska, there is not much left to be discovered. that means that most of these places are mature exploration provinces and is not much left to be found. and that is why that graph that i showed you on the first slide had declining production from those conventional resources and why the unconventional resources are so attractive as an exploration target. well, this isn't the whole story. i just was talking about onshore u.s. and state waters. our sister bureau at the
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department of interior, bureau of ocean and management uses very similar techniques to the ones we use at the usgs for estimating uncovered resources i don't have shore on the continental shell. and that ends up being a fairly large resource. and i want to point out, this is a conventional resource. there is so far no economic incentive to go to the expense of doing the hydro fracking and that sort of thing offshore. but when you put all of that together, and i sort of put it together here for our domestic resources, undiscovered resources, it's up to over 1400 trillion cubic feet of gas. fairly substantial amount of gas. i don't know if you noticed, again on the first slide, i didn't point it out, but our domestic production is about 22 trillion cubic feet a year. i want to change now from talking about gas to talking about oil.
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we also do oil assessments. we do unconventional oil assessments, because these tight formations sometimes as well contain oil. the most commonly known is the backen formation in north dakota and montana. and that is illustrated here at about our mean estimate, about 3.64 billion barrels of oil, which is a substantial oil resource. we still have not completed all of our assessments, so this map will be updated over the next year. i want to turn briefly to this map from the energy information administration to show that shale basin or shale formations occur throughout the united states. not everywhere. but looking at a map like this, in combination with our resources estimates gives planners, policymakers an idea of where future production might occur, in addition to the
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ongoing production we have right now, and be able to predict where infrastructure might need to be built, for example. or where impacts might need to be mitigated. i want to just leave you with this worldwide look. we talked about resources within the united states. undiscovered resources. there is another category of gas which we have found. so far i was talking about what we haven't found yet or are estimating is out there. what we have in terms of proved reserves in north america is about 346 trillion cubic feet of gas. but you can see there are much larger reserves in other parts of the world, particularly euras eurasia, russia in particular and the middle east. and finally, just to give you an idea of what the change or the boon in production and some of these basins is, i'm going to show you an animated map of the
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williston basin and the development of the backen formation. and you can see the production history building on the lower left corner of that graph. as you can see, quite an increase in the number of wells, over a relatively few number of years. thank you very much, doug, for the presentation. our second speaker tonight is dennis riser, hydrologist in pennsylvania since 19 8. he is currently working on projects to estimate ground water recharge rates, model groundwater surface water interactions and sample baseline
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water quality of streams and wells of marcellus shale gas development in pennsylvania. dennis received a master's degree from indiana university, bachelor's degree from miami university. and dennis tonight will discuss some of the major water availability and quality challenges associated with natural gas development with a focus on the marcellus shale in pennsylvania. >> thank you, dave. i would like to talk about water issues tonight associated with marcellus shale. and doug ended up showing the gas boom and the backen shale in north dakota and montana. similar things happening here in pennsylvania where i'm from. this map shows that in the last five years have been 10,000 sites permitted for marcellus shale wells in the state of
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pennsylvania. 5,000 of those sites have actually been drilled. so significant boom in drilling is occurring. and associated with that are, of course, some related water issues. part of what's happening in pennsylvania that's interesting is that, you know, this is a state that's not a stranger to oil and gas development. but the northeast part of the state is really has not experienced historic development of oil and gas resources. so everything is pretty new in the northeastern part of pennsylvania. so i'm going to talk about a few of the water issues that i think are interesting that i'm hearing on the news, and that i'm hearing come across my desk. the first is erosion and sedimentation. so erosion and sedimentation can occur well before any hydraulic fracturing occurs and before the well is drilled. we have to have a pad and access road.
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and you can see on this slide, which is in a pretty undisturbed area in the state forest of pennsylvania that the -- that the well pad is a significant footprint on the landscape. marcellus well pads tend to be pretty large compared to conventional oil and gas well pads. this is about three to eight acres, depending on how water is handled. in this slide, you can see the water is actually stored in a pond right off the pad. the roads tend to be charge to handle all the truck traffic that needs to go up and down, transporting water and chemicals to the site. you can see in this slide that a lot of the -- at least in this case, developments occurring on pretty rugged terrain. so any surface disruption can easily cause erosion and sedimentation if proper mitigation is not done. and those are very large well pads. they concentrate the industrial
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activity to that one large disturbed area. but they do have the advantage in that multiple laterals can be drilled from that same well pad. so a lot of the shale can be accessed from one location on the surface that's disturbed. in this case, you can see a well that's planned with five laterals, about 3 to 5,000 feet in length. and i've heard of laterals going out as far as 9,000 feet. this is a planned gas field build-out in state forest where you can see how the -- the development can be planned in a way that doesn't create much of a footprint on the landscape. this is a 9,000-acre development or lease. it's almost 15 square miles. and it's going to be tapped with only 15el with pads on the surface. so to put that in perspective, a more conventional type
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exploration orrel with field build out using 80 acre centers or 80-acre spacing of the wells would look something like this. and there would be ten times or more well pads on the surface. so the number of wells is a big deal, especially when you consider that each one of the wells has to have an access road and a pipeline, which, again, you're disturbing the surface, you're causing forced fragmentation, and possibility of erosion and sedimentation. so any way that the surface disruption could be minimizeded is a good thing. and gas operators are trying to do that in many cases. spills and leaks. certainly something that's not restricted to the oil and gas industry, but it's definitely a water concern. we have a lot of water being handled, infect injected at high pressures, chemicals being used along with the water.
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lots of truck traffic to transport these materials, so lots of opportunities for spills and leaks. on some of the pads that i've visited, we see the operators trying to mitigate the possibility of any leaks or spills by things like these liners and berms. here's an example of a pad where the water and the drill cuttings are held in ponds, surface ponds. of course, even if those ponds are lined, which they almost always are, you worry about is the liner leaking or are the ponds likely to be over top. what i've seen in the field, wells that i've visited, have containerized all of their handling of water and drilling fluids, like the drilling mud. so that these yellow tanks would be tanks that instead of having ponds, the tanks are holding the water on site. it's going to be used for the hydraulic fracturing. so then they can keep the water
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in a closed loop system and minimize any potential for leaks and spills. same with the cutting. when you drill a well, you're using a drilling mud that's down -- in the hole with the bit and the bit is grinding up the rock and the rock cuttings come up. again, they try to containerize and keep the mud in a closed loop system, where they can continually recycle the mud, drop the rock cuttings out, put those in a container, stabilize them. then it's a landfill. in pennsylvania, i'm told that pennsylvania landfills take about 1 million tons of drill cuttings per year. and hydraulic fracturing. that's what we hear on the news all the time. water concerns about hydraulic fracturing procedure. a lot of the issues i hear involve the amount of water used, which is considerable. the chemicals that are used along with the water and sand.
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what happens to that water when it's injected in the ground and what's the quality of the water when it flows back to the surface. i'll touch briefly on those issues. the amount of water used for hydraulic fracturing averages 4.5 million gallons per well. most of it is from surface water, mainly streams. and even the 32% water that comes from public supplies, which is purchased from water purveyors, most of that is from surface water supplies too. so very little ground water being used in pennsylvania for hydraulic fracturing. here you see a holding pond that is being used to -- they're filling it for use for hydraulic fracturing. that pond holds 5 million gallons of water. each one of those trucks in the picture down below -- actually, those trucks are feeding into
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the pipe lien you see, and the water is coming from the trucks into the holding pond. each one of the trucks is 5,000-gallon truck. so to get 5 million gallons of water, those -- 1,000 truckloads of water needs to be used to fill that pond. so i know where they're getting water, and for this particular well, it's from the creek, a two-and-a-half hour round-trip from the well site. so there is a lot of truck traffic on the road associated with this shale gas operation. us susquehanna river basin organization made this graph. the total amount of water they think is going to be used for hydraulic fracturing purposes in pennsylvania. and that's what you see in the yellow -- yellow box there. it's pointing to the usage by the gas industry that they have projected. 30 million gallons per day. and they have compared this against other water uses in the
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basin for water supply, energy production, recreation, et cetera. and just to give you a perspective that this is really not a huge amount of water for the us is question hannah basin, it's a pretty water rich base and i know has other uses that are much betterer than the shale gas we use. however, the total water use is really not the issue. the issue is where are you taking the water, and when are you taking it? the location of the withdrawal is very important. here you see a withdrawal from a very small stream, and you can easily imagine that if they put too many straws drawing too much water, you could easily dry up that small stream. so the susquehanna river base association has certain places where certain withdrawals are allowed to be taken, permitted withdrawal points. there's over 170 of them in the susquehanna basin. as i mentioned, it's not just where you take the water, but the timing.
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the time of year that you take the water. here you see a graph, called a hydro graph, showing stream flow and like combin creek during 2011. 2011 was the wettest year in history in pennsylvania. we had a very wet spring and a very wet fall. but in the summer, during july and august, was a very dry period, where the susquehanna river basin commission looked at the stream flow hydrographs and said no, the industry cannot take anymore water from 36 of these permitted withdrawal points. so i guess the answer to the question, is there enough water is, yes, there is plenty of water, adequate water exists, but not everywhere and not at all times. another question about the hydraulic fracturing that's in the news a lot is the chemicals that are mixed with the water and the sand and the sand is used as the prop that you saw in that animation. what are those chemicals, what do they consist of?
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recently industries disclosed a lot more of the chemicals they're using. i got this information off of a publicly available web page called frac focus. and that was put together by the ground water protection council, along with industry, so that as -- as a portal, really, for disclosing the chemicals being used. i just picked a well at random in northern pennsylvania, and these were the actual percentages of chemicals used. there was only .3% of the total volume that was injected were added chemicals. now, .3% is not very big percentage, but when you put in 4.7 million gallons, it turns out that that's about 11,000 gallons of chemicals. so, you know, significant chemical usage is happening here. if you look at the circle on the right, i've broken down the chemicals, and you can see that the acid fraction is --
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contributes probably three quarters of the amount of the added chemicals. the acids used to clean out the well that you saw in the animation where they perforate the casing and shoot into the rock and then they follow that up with an acid treatment to clean out the -- you know, the holes that are made into the casing and rock. some of the other compounds you can find on frac focus are mainly compounds used to keep the holes open. so they don't get clogged up bacteriaal activity or just with corrosi corrosion. then you've injected the water, the fracking process, you release the pressure and then that water comes back. at least some of it comes back. again, the susquehanna river basin commission says that between about 5 to 15% of the water that's injected comes back. this graph shows the salinity of the water and different sampling
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points at different times of the flowback. so after the first day of flowback, this well was sampled and found it had 19,200 milligrams per liter, total dissolved solid. that's pretty salty. sea water is 35,000, approximately, milligrams per liter of total dissolved solid. then you can see as time goes on in this flowback water continues to come out, although less and less volumes, the salinity increases dramatically. so after two weeks, we're -- flow back consists, hardly any of the original water probably was put in. mostly the brine that exists naturally in the formation. very salty, six times the salinity of the sea water. and then waste disposal, the water comes back as flowback and then you have to dispose of it properly. and the disposal has been the big issue. and early in the shale gas play in pennsylvania, by early i
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mean, you know, four or five years ago, a lot of the -- a lot of the water water is being sent to municipal treatment plants, which really were not well-suited or designed to handle the flowback chemistry. the high dissolved solid loads. so that practice has largely been stopped in pennsylvania. there are some industrial treatment plants that can treat the water to various degrees, but there's not a lot of those. i've toured one of the treatment plants and the polished water, which starts out as 200,000 milligrams per heater water after it's been distilled comes out as 100 milligrams per liter, finished product. and then that can be disposed of safely through the municipal treatment plant. a lot of water is sent to neighboring states for deep well injection. at least that's been the case in
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the previous few years and the next speaker is going to talk more about deep well injection. a lot of the operators are telling me now that they are 100% recycleling their frac water. so they use the frac water in a job. what returns to the surface, they containerize, they do some treatment on it, and then they use it on their next well. so that's a very encouraging development. this is a really nissan medication. it's from southwestern energy. it shows what you like to see. you have drilled the well into the target formation down at the bottom there. marcellus shale, in our case. you've isolated that well with multiple strings of steel casing and cement. and producing red gas bubbles, in this case, from the marcellus growing up to the surface. you notice that there's two
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formations that are above the marcellus that also contain gas shown by the little red circles. and that's a very common occurrence in pennsylvania. it's not just the marcellus shale that has gas. but there's lots of layered shales above the marcellus, and sandstones too, that naturally contain small amounts of natural gas. and in drilling for the marcellus shale, the operators have to drill through those shallower gas-producing units. sometimes what they want to do is seal those off. so small amounts of gas can't escape and contaminate the environment. here's an example of how that contamination can happen if the cement job on the well is not done properly. in this case, in the circular insert, you can see an illustration, a cartoon, showing the cement has not bonded properly to the rock. and that allows some of the gas to seep out of that
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shallow-producing zone, move up the annulus of the well, between the two casing strings that has not been cemented and find its way out into the environment and maybe contaminate some fresh water. so the industry tries hard to prevent this. this is what we call stray gas. and it's one way that gas can get into the environment. it's not the only way. but a lot of the cases of gas migration that you hear about that are blamed on hydraulic fracturing are more likely caused by this kind of well construction problem. so all of these issues i talked about, people are asking, what's the cumulative impact or cumulative effect of all those things put together, all those wells? well, i don't know, but it's going to depend ultimately on the regulations. the regulations have changed twice in pennsylvania in the last couple years. those, i'm sure, are going to be
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modified as time goes on. also action by industry. the procedures and practices that industry has been taking has changed over the last five years tremendously. and also monitoring and research. that's where usgs comes in. monitoring the quality of our surface and ground waters is very important. and of really fundamental importance is getting a snapshot of the baseline quality of these resources before drilling comes in. you can see in pennsylvania and some of these areas, the horse is already out of the barn. it's tough to find the collect line basin conditions now. and also research. research needs to be done in a lot of issues where we really just don't know what's going on. one example is when we do see chemicals -- contaminants in the environment, we need to find ways to fingerprint the con
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tamnants so we know what the resources are, are they naturally occurring, are they coming from a leak in a gas well. thanks very much. >> thank you very much, dennis. our third speaker tonight is bill leaf. associate coordinator for the usgs earthquake hazard here. bill is a seismologist who oversees the global earthquake monitoring and capabilities of the usgs. bill serves as a usgs acting associate director for natural hazards from 2010 to 2011 and the past two years, bill has been called upon many times for his expertise on the subject of triggered earthquakes, including those associated with hydraulic fracturing. in just the past month, bill has given several abbreviation to the senior administration and congressional staff. bill joined the usgs in 1986
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after receiving a doctoral degree in seismology and geology from columbia university. he served as chief of the usgs special gee logic studies group and senior technical adviser to the assistant secretary of state for verification compliance with nuclear test band treaties. and bill will conclude tonight's lecture by discussing how disposal of waste fluids through injection into deep rock formations can generate earthquakes. >> thanks, dave. so induced earthquakes, i'll also refer to this as trigger earthquakes, or induced size misty, all the same phenomenon. and it's quite a hot topic as you probably know from reading the newspaper in the last few years, or in the last year, we've had either likely or potentially triggered earthquakes from the disposal activities that dennis talked about in arkansas and

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